Abstract

When dispersal is limited, crosses between different regions may generate progeny of higher fitness than crosses within regions, due to the fact that individuals from the same region are more likely to share the same recessive deleterious alleles. This phenomenon (termed heterosis) generates a selective force favouring dispersal; however, the importance of heterosis on dispersal evolution has been a subject for debate. In this paper, we use computer simulations representing deleterious mutations occurring over a whole genome (of arbitrary map length R) to explore the magnitude of heterosis, and its effect on the evolution of dispersal. These results show that heterosis may have important effects on dispersal when it is in the upper range of values observed in natural populations, which occurs in our simulations when the genomic deleterious mutation rate U is also in the upper range of observed values. Comparing the results with extrapolations from an analytical two-locus model indicates that the effect of heterosis is mainly driven by pairwise associations between the locus affecting dispersal and selected loci when U is not too high (roughly, U < 0.5), whereas higher order associations become important for higher values of U.

Keywords

Publication History

Received 4 December 2008; revised 19 February 2009; accepted 2 March 2009

Supporting Information

Appendix S1 One-locus model of heterosis.

Appendix S2 Simulation programs.

Appendix S3 Two-locus model of dispersal evolution.

Appendix S4 Absolute evolutionarily stable dispersal rates.

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Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.